Solvent and process of preparing same.



HARRY O. CHUTE, OF CLEVELAND, OHIO.

SOLVENT A ND PROCESS OF PREPARING SAME.

Specification of Letters Patent.

Patented Feb. 26, 1907.

Application flied January 14. 1907. Serial No. 352,268.

To all whom it may concern:

Be it known that T ial ABBY O. CHUTE, a

I citizen of the UnitedStates, residing 1n Cleveland, inthe county of Cuyahoga and State of Ohio, have invented certain new and useful Improvementsin Solvents and Processes of Preparing the Same; and I do hereby declare the following to be a full, clear, and exact description of the same, such as will enable others skilled in the art to make and use the same. 4

This invention relates to'solvents and processes of preparing the-same, and consists in an acetic ester protected against hydrolysis by the dpresence of another solvent and in a metho of producing such a compound solvent, all as more fully hereinafter set forth and as claimed.

The acetic esters of thealiphatic and other alcohols are excellent solvents for resins, and particularly for the resins accompanying the rubber gums-in crude rubber, but suffer from the disadvantage of comparative instability in the presence of water especially when heats ed, as they tend to brea up to a slight extent by tion of a molecule of water and reformatio of acetic acid and the alcoholfrom which the ester is derived. While this decomposition is seldom far-reaching, only a small amount occurring with any moderate amount of water in a moderate length of time, it is nevertheless suflicient to render the use. of such esters unduly costly for the purpose I extracting the resins from crude rubber, an operation to which they are otherwise well adapted. The crude rubber always carries more or less moisture, which of course .mixes with the solvent in extracting resin and must afterward be removed to fit the solvent for further use? In this removal the most suitable way is fractional distillation;

and that the mixtures so but this involves heating the ester and water together and in consequence more or less 0 the stated hydrolytic decomposition. I have discovered that by mixing t solvents less sensitive to water this tendency to dissociation or hydrolysis may be obviated formed are well adapted both for removing resins from crude. rubber and for miscellaneous purposes.- As the second solvent I prefer a ketone, and more articularly acetone, the ketones being, like t e lower acetic esters, soluble in water and good resin solvents. Besides the true acetone or dimethyl ketone there is a body known in commerce as drl f byt hese esters with 'tained by the use ofone of these methyl acetone,

which whilequite similarin most of its characteristics in others is distinctly different. The true acetone is customarily prepared by pyrolytic decomposition of acetates or acetic acid, while the methyl acetone 1s a low-boil ingfraction of wood-spirit. acetone may be used tor my purposes, I refer the methyl acetone when preparing a owboiling solvent.

As the acetic ester I prefer the methyl compound. Methyl acetate in admixture with either acetone or methyl acetone forms a very desirable solvent both for removing rubber resins and for general use as a solvent. The boiling oints of methyl acetate and Though the true acetone lie very close together, there being but about three degrees'difierence, and the mixture can therefore be easily fractionated away from water and other bodies as a whole. The same is true of a mixture of methyl acetate and methyl acetone, and this mixture offers certain advantages as a solvent over the mixture just stated. Methyl acetone may also be used in admixture with other acetic esters, such as ethyl acetate. Other and higher boiling ketones, such as methyl-propyl ketone, may be used in conjunction wit estegs when higher-boiling mixtures are desire A mixture of methyl acetate'and methyl acetone I find to be practically insensitive to the hydrolytic action of water, and itmay be used for extracting crude rubber and separated from the res n and water extracted by boiling mixture of about equal quantities of the two solvents dissolves sometwenty per cent. of resin, such as the resin from crude pontianak rubber. V

Methyl acetate may be protected from hyo by other solventsas, for instance, e use of methylalcohol. The described hydrolysis, in the presence of a 'ven nantity of water, goes ontill a' co ain' ba ance obtains between the undeeomposed acetic ester and its hydrolytic products-methyl alcohol and acetic acid in, the case of moth?) acetate. This balance may as well be 0 roducts as in other words, if met yl alcohol be already present in sufiicient amount hydrolysis may be restrained alto ether. About ten per cent. of methyl alcoho inadmixture with methyl. acetate in practice proves suflicient, though more may be used.

of both, or,

acetic.

off substantially without practical loss, so that it may be repeatedly reused; 'A'

'The methyl acetone in the wood-spirit is nary commercial gray acetate of lime.

- Use of the described compound solvents for extracting crude rubber forms the subject of a cop'ending application, Serial No. 351,868, filed January 11, 1907.

A very advantageous, cheap, simple, and ready method of forming my preferred composition of-. methyl acetate and methyl acetone conslsts in directly converting the methyl alcohol of ordinary commercial woods lrit into methyl acetate, using any suitllle acetate and acid for this purpose.

not affected by this operation, and remains in admixture with the methyl acetate formed. Ordinary wood-spirit usually contains about thirty per cent. of methyl acetone. I, how ever, usually prefer a greater proportion of methyl acetone in my com ound solvent: than is given by this simp e method, though any roportion is useful. A good method of obta ning a solvent with higher amounts. of methyl acetone is to fractionaltiglthe crude alcohol in a columud-still rect' 'ng. a paratus, cutting out an reserving the iirst portions, which boil around 56 centigrade. The remaining portion, which is freed from the bulk of the methyl acetone, can be withdrawn from the still and used directly, but I prefer to distil it also, cool, and manufacture into the methyl acetate. This may easily be done in the following manner: Ina covered iron vessel I place two hundred and ten pounds of 66 Baum commercial sulfuric acid. Into this, through a small lead pipe or other suitable means, I carefully and slowly pass nineteen gallons of the urified wood-alchohobtained as just des'cri ed. It is best introduced at the bottom of the body of acid, taking care not to allow the mixture to become hot enough to evolve methyl ether. After the mixture is made and has become sufiiciently cool it is poured over three hundred and four pounds of orlcllli- T s is best done in a retort with a stirrer or other i convenient form of covered vessel, The 1 mixture is heated and stirred till all volatile bodies are removed, suitable condensing j means being used to recover them. From I the condenser will flow about thirty-seven l gallons of methyl acetate of sufficient purity j for most purposes. It may be rectified, but this ordinarily not necessary. To this methyl acetate I add about an equal volume i of the methyl acetone prepared in the preliminary distillation of the wood-spirit. The mixture may be rectified, if desired.

A solvent containing less methyl-acetone, butsufiicient for protective action for most purposes, may be prepared by substituting for the nineteen gallons of urified alcohol stated above twentyfive gal ons of ordinary ninety-five-per-cent. alcohol as made in the ordinary retort charcoal process. This contains about thirty er cent. methyl acetone, which goes through the process and finally remains in admixture with the methyl acetate produced. The operation gives about forty-three gallons of solvent containing about fifteen per cent. of methyl acetone.

The pure methyl acetone, as recovered from Wood-spirit, has about the same boilingpointnamely, around 56.5as the true acetone from acetates, but yields only about half as much chloroform on chlorinating in the usual way as does the true acetone. The structural differences of the two substances are unknown.

What I claim is 1'. As a new composition of matter, a compound solvent comprising methyl acetate and a protective solvent.

2. As a new composition of matter, a compound solvent comprising methyl acetate and a ketone.

3. As a new composition of matter, a compound solvent comprising methyl acetate and an acetone.

4. As a new composition of matter, a compound solvent comprising methyl acetate and methyl acetone.

5. As a new composition of matter, a compound solvent comprising an acetic ester and methyl acetone.

6. The process of preparing a compound solvent which consists in mixing methyl acetate with a protective solvent.

7. The process of preparing a compound solvent which consists in fractionating woodspirit, reserving the low-boiling portion, converting the residue into methyl acetate and mixing the methyl acetate with the stated low-boiling fraction in desired proportions.

In testimony whereof I affix my signature in the presence of two Witnesses.

HARRY O. CHUTE.

Witnesses:

B. L. CHADWELL, K. P. MOELROY. 

